The overall objective of this research is to develop a behavioral treatment for Raynaud's disease which might also be applicable to other related disorders of peripheral circulation. Three experiments are proposed. The first would assess the comparative relevance of three commonly-used measures of peripheral blood flow for the treatment of Raynaud's disease by comparing the skin temperature and photoplethysmographic responses (reflectance method) of both Raynaud's patients and normals to physical and emotional stress. The second experiment would compare the efficacy of analogue and binary biofeedback systems in training vasodilation in normal subjects. In the third study, a biofeedback treatment would be designed employing the measure of blood flow found most relevant to Raynaud's disease in Experiment I and the feedback system found most effective in Experiment II. The clinical utility of this technique would then be assessed by comparing it to a simple, non-specific relaxation procedure and a placebo control in the treatment of Raynaud's patients. Responses to physical and emotional stress, as well as subjective reports of symptom severity would be used as dependent variables.